Stellites are oxidation resistant alloys of varying compositions of basically tungsten, cobalt, chromium, and nickel. Waste grindings produced as a result of various machining operations with stellite alloy material represent a sizable source for reclaiming metal values such as tungsten, cobalt, and chromium.
Recovery of cobalt from stellite grindings by existing techniques has resulted in poor yields due to the presence of large amounts of chromium. Presently chromium is removed from chloride solutions as the hydroxide by adjusting the solution ph to about 3.5 and filtering to remove the insoluble hydroxide. Although greater than about 95% of the chromium is precipitated, about 20% to about 40% of the cobalt is also contained in the solid. Iron also precipitates and reports with the chromium solids. Chromium is not recovered from his solid due to the large amounts of cobalt and iron still associated with it.
A method to separate chromium from cobalt and efficiently recover both metals from such material would be desirable.